Minion Damage: 15% of what?

I have been dealing with summoning for a month now, and I do everything a good zombie parent should be doing, i.e. choosing support gems and passives that give them every advantage possible.

But I STILL do not understand minion damage mechanics. When I choose a passive that gives my minions 15% more damage I am all like "yay!", but 15% of what? Under the tool tips for my zombies it says I am doing 95 DPS (per zombie I guess). What is this based off of? The damage my wand could do if I were using it as a weapon and not as a vessel to hold my spells?

I tried doing some whetstones on my wand to see if increasing its damage would act as a platform for all of these "+15%" passives, but it does not seem to.

Google has not helped me on this matter, unless of course it is somewhere past page 5.

The zombies are a monster. Like all monsters they have their own base damage, it's not based on your weapon. You can add base damage to them with support gems as well.
"DPS" shown on Raise Zombie is not a valid value, we just don't have a way to disable it for only certain skills yet.

There is no answer because the forget... same as in Titan quest and titan quest immortal thrones... what a lobely game is path of exile and just some small details about minion damage and attack speed make it really bad because u will never know what weapons are best to use it.. what happen to you people why cant just make best game on market ... this that will show u just 30 % damage is mean nothing we want to know what is that damage... ohh god